Robotic fingers and end effectors including same

ABSTRACT

A robotic end effector includes a finger and at least one actuator. The finger extends from a proximal end to a distal end along a finger axis. The finger includes a first phalanx proximate the proximal end, a second phalanx proximate the distal end, and a knuckle joint including at least one vertebra interposed between and separating the first and second phalanxes. The knuckle joint is configured to permit the second phalanx to pivot relative to the first phalanx about a pivot axis transverse to the finger axis. Each vertebra has an axial thickness extending along the finger axis and a lateral width extending perpendicular to its axial thickness, and its lateral width is greater than its axial thickness. The at least one actuator is operable to move the second phalanx relative to the first phalanx about the pivot axis.

FIELD

The present invention relates to robots and, more particularly, torobotic fingers and end effectors.

BACKGROUND OF THE INVENTION

Robotic end effectors or graspers are commonly used to manipulate and/orgrasp objects in a selected environment. The environment may bestructured or unstructured. Such robotic end effectors or graspers maybe provided on robotic arms. Robotic end effectors may be provided withfingers adapted to perform a range of actions and manipulations.

SUMMARY OF THE INVENTION

According to embodiments of the invention, a robotic end effectorincludes a finger and at least one actuator. The finger extends from aproximal end to a distal end along a finger axis. The finger includes afirst phalanx proximate the proximal end, a second phalanx proximate thedistal end, and a knuckle joint including at least one vertebrainterposed between and separating the first and second phalanxes. Theknuckle joint is configured to permit the second phalanx to pivotrelative to the first phalanx about a pivot axis transverse to thefinger axis. Each vertebra has an axial thickness extending along thefinger axis and a lateral width extending perpendicular to its axialthickness, and its lateral width is greater than its axial thickness.The at least one actuator is operable to move the second phalanxrelative to the first phalanx about the pivot axis.

In some embodiments, each of the first and second phalanxes has aphalanx length that is at least 2 times the axial thickness of each ofthe vertebrae.

In some embodiments, the lateral width of each of the vertebrae is atleast 1.5 times its axial thickness.

According to some embodiments, each of the vertebrae has a heightperpendicular to each of its axial thickness and its lateral width, andthe axial thickness of the vertebra varies across the height of thevertebra.

In some embodiments, at least one of the vertebrae includes a nonplanarbearing surface that engages an adjacent bearing surface of one of thefirst phalanx, the second phalanx, and an adjacent vertebra. The bearingsurface may have at least one substantially planar section. In someembodiments, the bearing surface includes: an outer stop face configuredto limit rotation of the first phalanx about the pivot axis in a firstbending direction; and an angled inner face disposed at an oblique angleto the outer stop face to permit rotation of the first phalanx about thepivot axis in a second bending direction opposite the first bendingdirection. In some embodiments, the bearing surface further includes aneutral face located between the outer stop face and the inner angledface and disposed at an oblique angle to the outer stop face and theangled inner face.

According to some embodiments, the at least one vertebra includes aplurality of vertebrae serially arranged between the first phalanx andsecond phalanxes. In some embodiments, the at least one vertebraincludes at least three vertebrae serially arranged between the firstphalanx and second phalanxes. Each of the plurality of vertebrae mayinclude a nonplanar bearing surface that engages an adjacent bearingface of one of the first phalanx, the second phalanx, and an adjacentvertebra. In some embodiments, at least two of the vertebrae havedifferent axial thicknesses from one another.

The robotic end effector may further include a third phalanx proximatethe distal end of the finger, and a second knuckle joint including atleast one vertebra interposed between and separating the second andthird phalanxes. The second knuckle joint is configured to permit thethird phalanx to pivot relative to the second phalanx about a secondpivot axis transverse to the finger axis. Each vertebra of the secondknuckle joint has an axial thickness and a lateral width extendingperpendicular to its axial thickness, and its lateral width is greaterthan its axial thickness. The at least one actuator is operable to movethe third phalanx relative to the second phalanx about the second pivotaxis.

The robotic end effector may include an elongate, flexible guide memberextending from the first phalanx to the second phalanx and through theat least one vertebra to flexibly couple the first and second phalanxesand the at least one vertebra and retain the at least one vertebrabetween the first and second phalanxes. In some embodiments, the guidemember has a Young's Modulus of less than about 2.4 GPa at 23 degreesCelsius.

The robotic end effector may include a tendon cable associated with theat least one actuator for moving the second phalanx relative to thefirst phalanx about the pivot axis, wherein the tendon cable extendsthrough the at least one vertebra and applies an axially compressiveload to the first phalanx, the second phalanx and the at least onevertebra to hold the first phalanx, the second phalanx and the at leastone vertebra together and in contact with one another. The robotic endeffector may further include a tensioning mechanism to maintain theaxially compressive load. In some embodiments, the tensioning mechanismincludes a spring applying a biasing load to the tendon cable.

The robotic end effector may include first and second tactile sensorsmounted on the first and second phalanxes, respectively, wherein the atleast one vertebra does not or do not include tactile sensors mountedthereon. The robotic end effector may further include electrical wireselectrically connected to the second tactile sensor and extending fromthe second phalanx and through the at least one vertebra.

In some embodiments, the at least one vertebra is or are formed of apolymeric material.

According to embodiments of the invention, a robotic end effectorincludes a finger and at least one actuator. The finger extends from aproximal end to a distal end along a finger axis. The finger includes: afirst phalanx proximate the proximal end, the first phalanx including afirst phalanx cavity therein; a second phalanx proximate the distal end;and a knuckle joint coupling the first and second phalanxes andconfigured to permit the second phalanx to pivot relative to the firstphalanx about a pivot axis. The finger further includes a tactile sensorassembly mounted on the second phalanx, first and second lead wiresconnected to the tactile sensor assembly, and a remote receiver. The atleast one actuator is operable to move the second phalanx relative tothe first phalanx about the pivot axis. The first and second lead wiresextend sequentially from the second phalanx, through the knuckle joint,through the first phalanx cavity, and to the remote receiver.

In some embodiments, the tactile sensor assembly includes a resistivesensor.

According to some embodiments, the resistive sensor includes: asubstrate having an inner surface; first and second electricallyconductive traces disposed on the inner surface of the substrate; and anelectrically conductive layer having an inner surface facing the innersurface of the first substrate. The first and second lead wires areconnected to the first and second electrically conductive traces,respectively. At least one of the substrate and the electricallyconductive layer is configured to deform responsive to an applied forceon the resistive sensor and thereby place the electrically conductivelayer in contact with the first and second electrically conductivetraces to electrically connect the first and second electricallyconductive traces through the electrically conductive layer.

In some embodiments, the electrically conductive layer is asemiconductor layer. In some embodiments, the semiconductor layer has asheet resistance in the range of from about 2 kiloohms/square to 20kiloohms/square. The semiconductor layer may be a polymeric filmimpregnated with an electrically conductive filler.

In some embodiments, an electrical resistance across the first andsecond lead wires is a function of the applied force, and the remotereceiver is operative to detect the electrical resistance via the firstand second lead wires.

According to some embodiments, the substrate is rigid and is interposedbetween the electrically conductive layer and an outer surface of thesecond phalanx. In some embodiments, the resistive sensor does notinclude any electronic components on the side of the electricallyconductive layer opposite the substrate. The substrate may be a printedcircuit board (PCB). In some embodiments, first and second lead wiresare terminated at the PCB.

The robotic end effector may include a spacer interposed between thesubstrate and the electrically conductive layer, wherein the spacermaintains a gap between the electrically conductive layer and the firstand second traces in the absence of an applied force.

The robotic end effector may further include: a second resistive sensormounted on the second phalanx; and a third lead wire connected to thesecond resistive sensor and extending sequentially from the secondphalanx, through the knuckle joint, through the first phalanx cavity,and to the remote receiver. In some embodiments, the substrate includesa printed circuit board (PCB), and the first and second resistivesensors are each mounted on the PCB. In some embodiments, the PCB isnonplanar, and the first resistive sensor is disposed at an anglerelative to the second resistive sensor. According to some embodiments,the robotic end effector includes a switching circuit operative toalternatingly: electrically connect the first and second lead wiresacross the first resistive sensor to generate a signal to the remotereceiver corresponding to a force applied to the first resistive sensor;and electrically connect the third and second lead wires across thesecond resistive sensor to generate a signal to the remote receivercorresponding to a force applied to the second resistive sensor.

The robotic end effector may further include a protective cover layerover the tactile sensor assembly. In some embodiments, the protectivecover layer is formed of a compliant elastomeric foam.

According to some embodiments, the robotic end effector furtherincludes: a base; a second knuckle joint coupling the first phalanx andthe base, wherein the second knuckle joint is configured to permit thefirst phalanx to pivot relative to the base about a second pivot axis; asecond tactile sensor assembly mounted on the first phalanx; third andfourth lead wires connected to the second tactile sensor assembly; andat least one actuator to move the first phalanx relative to the baseabout the second pivot axis. The first, second, third and fourth leadwires extend through the second knuckle joint and to the remotereceiver.

The robotic end effector may further include: a third phalanx; a thirdknuckle joint coupling the second phalanx and the third phalanx, whereinthe third knuckle joint is configured to permit the third phalanx topivot relative to the second phalanx about a third pivot axis; a thirdtactile sensor assembly mounted on the third phalanx; fifth and sixthlead wires connected to the third tactile sensor assembly; and at leastone actuator to move the third phalanx relative to the second phalanxabout the third pivot axis. The second phalanx includes a second phalanxcavity therein. The fifth and sixth lead wires extend sequentiallythrough the third knuckle joint, the second phalanx cavity, the firstknuckle joint, the first phalanx cavity, and the second knuckle jointand to the remote receiver.

In some embodiments, the knuckle joint includes at least one vertebrainterposed between and separating the first and second phalanxes. Thepivot axis is transverse to the finger axis. Each vertebra has an axialthickness extending along the finger axis and a lateral width extendingperpendicular to its axial thickness, and its lateral width is greaterthan its axial thickness. The first and second lead wires extend throughthe at least one vertebra.

Further features, advantages and details of the present invention willbe appreciated by those of ordinary skill in the art from a reading ofthe figures and the detailed description of the embodiments that follow,such description being merely illustrative of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a robotic arm and an end effectoraccording to embodiments of the invention, wherein the end effectorincludes robotic fingers according to embodiments of the invention.

FIG. 2 is a rear perspective view of one of the robotic fingers of FIG.1.

FIG. 3 is an exploded, front perspective view of the robotic finger ofFIG. 2.

FIG. 4 is a side elevational view of a vertebra forming a part of amedial knuckle joint of the robotic finger of FIG. 2.

FIG. 5 is rear view of the vertebra of FIG. 4.

FIG. 6 is rear perspective view of the vertebra of FIG. 4.

FIG. 7 is front perspective view of a vertebra forming a part of aproximal knuckle joint of the robotic finger of FIG. 2.

FIG. 8 is a fragmentary, side view of the finger of FIG. 2.

FIG. 9 is a fragmentary, bottom view of the finger of FIG. 2.

FIG. 10 is a fragmentary, cross-sectional view of the finger of FIG. 2taken along the line 10-10 of FIG. 9.

FIG. 11 is a fragmentary, cross-sectional view of the finger of FIG. 2taken along the line 12-12 of FIG. 2, wherein the finger is shown in aneutral position.

FIG. 12 is a cross-sectional view of the finger of FIG. 2 taken alongthe line 12-12 of FIG. 2, wherein the finger is shown in the neutralposition.

FIG. 13A is a cross-sectional view of the finger of FIG. 2 taken alongthe line 12-12 of FIG. 2, wherein the finger is shown in a closedposition.

FIG. 13B is an enlarged detail view of area 13B designated in FIG. 13A.

FIG. 14 is a cross-sectional view of the finger of FIG. 2 taken alongthe line 12-12 of FIG. 2, wherein the finger is shown in an openposition.

FIG. 15 is a cross-sectional view of the finger of FIG. 2 taken alongthe line 12-12 of FIG. 2, wherein the finger is shown overloaded by anupward external load.

FIG. 16 is a cross-sectional view of the finger of FIG. 2 taken alongthe line 12-12 of FIG. 2, wherein the finger is shown overloaded by adownward external load.

FIG. 17A is a top view of the finger of FIG. 2 wherein the finger isshown overloaded by a sideward external load.

FIG. 17B is a cross-sectional view of the finger of FIG. 2 taken alongthe line 12-12 of FIG. 2, wherein the finger is shown overloaded by thesideward external load.

FIG. 18 is a fragmentary, cross-sectional view of the finger of FIG. 2taken along the line 18-18 of FIG. 19, showing a sensor system forming apart of the finger.

FIG. 19 is a bottom view of the finger of FIG. 2 including the sensorsystem of FIG. 18.

FIG. 20 is an exploded, perspective view of a sensor assembly forming apart of the sensor system of FIG. 18.

FIG. 21 is a perspective view of a printed circuit board forming a partof the sensor of assembly of FIG. 20.

FIG. 22 is a cross-sectional view of the finger and sensor system ofFIG. 18 taken along the line 22-22 of FIG. 19.

FIG. 23 is a rear perspective view of a robotic finger according tofurther embodiments of the invention.

FIG. 24 is an exploded, rear perspective view of the robotic finger ofFIG. 23.

FIG. 25 is a front perspective view of a robotic finger according tofurther embodiments of the invention.

FIG. 26 is an exploded, front perspective view of the robotic finger ofFIG. 25.

FIG. 27 is a cross-sectional view of the finger of FIG. 25 showing atensioning system of the robotic finger in different operationalpositions.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which illustrativeembodiments of the invention are shown. In the drawings, the relativesizes of regions or features may be exaggerated for clarity. Thisinvention may, however, be embodied in many different forms and shouldnot be construed as limited to the embodiments set forth herein; rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the invention to thoseskilled in the art.

It will be understood that when an element is referred to as being“coupled” or “connected” to another element, it can be directly coupledor connected to the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlycoupled” or “directly connected” to another element, there are nointervening elements present. Like numbers refer to like elementsthroughout.

In addition, spatially relative terms, such as “under”, “below”,“lower”, “over”, “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation in addition tothe orientation depicted in the figures. For example, if the device inthe figures is turned over, elements described as “under” or “beneath”other elements or features would then be oriented “over” the otherelements or features. Thus, the exemplary term “under” can encompassboth an orientation of over and under. The device may be otherwiseoriented (rotated 90 degrees or at other orientations) and the spatiallyrelative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. As used herein the expression“and/or” includes any and all combinations of one or more of theassociated listed items.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

The term “monolithic” means an object that is a single, unitary pieceformed or composed of a material without joints or seams.

Embodiments of the present invention are directed to robotic fingers andend effectors. A finger as disclosed herein may form part of a robot ora prosthetic apparatus. In particular, the robotic finger may form apart of an end effector and be used to manipulate and grasp objects in astructured or unstructured environment. The finger may be employed as afinger of a humanoid robot. Aspects of the inventive finger may enablelow cost manufacture of the finger and end effector.

With reference to FIGS. 1-22, a robot 5 (FIG. 1) according toembodiments of the invention is shown therein. The robot 5 includes andarm 7 and a robotic grasper or effector 10 according to embodiments ofthe invention mounted on an end of the arm 7.

The end effector 10 includes a base 20 and four fingers 100, 102, 104and 106 mounted on the base 20. Each of the fingers 100, 102, 104, 106is further provided with a respective sensor system 170 (FIGS. 18-22)and a respective drive system 150 (FIGS. 2 and 3). In the illustratedembodiment, the fingers 102, 104, 106 generally oppose the finger 100,which may be referred to as a thumb. The fingers 100-106 may beunderactuated.

The fingers 100, 102, 104, 106 may be identically or similarlyconstructed as discussed above. An exemplary finger 100 (i.e., thethumb) is described below, and it will be appreciated that thisdescription likewise applies to the other fingers 102, 104, 106.

With reference to FIG. 2, the finger 100 as a longitudinal axis A-A andextends axially from a proximal end 100A to a distal end 100B. Thefinger 100 includes a base member 110A (which includes an integralphalanx 110), a proximal phalanx 112, a medial phalanx 114, and a distalphalanx 116. The finger 100 further includes a proximal knuckle jointJP, a medial knuckle joint JM, and a distal knuckle joint JD.

The proximal knuckle joint JP pivotally couples the proximal phalanx 112to the base member 110A to permit relative rotation or pivoting betweenthe members 110A, 112 about a pivot axis PP-PP transverse orperpendicular to the longitudinal axis A-A. The medial knuckle joint JMpivotally couples the medial phalanx 114 to the proximal phalanx 112 topermit relative rotation or pivoting between the members 112, 114 abouta pivot axis PM-PM transverse or perpendicular to the longitudinal axisA-A. The distal knuckle joint JD pivotally couples the distal phalanx116 to the medial phalanx 114 to permit relative rotation or pivotingbetween the members 114, 116 about a pivot axis PD-PD transverse orperpendicular to the longitudinal axis A-A.

In embodiments, the proximal knuckle joint JP includes two proximalvertebrae V1, V2. The medial knuckle joint JM includes two medialvertebrae V3, V4. The distal knuckle joint JD includes two distalvertebrae V5, V6. Each of the knuckle joints JP, JM, JD further includesa pair of flexible, elongate connecting ligaments, tethers, or guidemembers 118. The vertebrae V1, V2 are serially arranged between theadjacent ends of the phalanx 110 and the phalanx 112. The vertebrae V3,V4 are serially arranged between the adjacent ends of the phalanx 112and the phalanx 114. The vertebrae V5, V6 are serially arranged betweenthe adjacent ends of the phalanx 114 and the phalanx 116.

The finger 100 further includes an inner tendon cable 156 and an outertendon cable 158, and a pin 149 securing ends of the tendon cables 156,158. As discussed below, the tendon cables 156, 158 extend through thebase member 110A and phalanxes 110, 112, 114, 116 and also form part ofthe knuckle joints JP, JM, JD.

The finger 100 may be further provided with tubular outer boots orcovers 148 (FIGS. 18, 19 and 22).

The base member 110A includes a housing 110B and the base phalanx 110integral therewith.

With reference to FIG. 11, each of the phalanxes 110, 112, 114, 116includes a body 120 and a central bore 122, an inner raceway 124A, andan outer raceway 124B extending axially fully through the body 120.While the body 120 is shown as a monolithic hollow tube, the body 120may instead be formed from two or more joined parts. In embodiments, thebody 120 may be formed of a pair of mated clamshells.

The phalanxes 112, 114, 116 each include a proximal bearing surface132A. The phalanxes 110, 112, 114 each include a distal bearing surface132B. Each of the bearing surfaces 132A, 132B is nonplanar and includesan inner section 134L and an outer section 134U (FIGS. 12 and 13A). Thebearing surfaces 132A, 132B of the phalanxes 112, 114, 116 also includea midsection 134M. In some embodiments, each of the sections 134U, 134L,134M is substantially planar and disposed at an angle to each of theother two sections. The distal phalanx 116 is further provided with apinhole 128 and a fingernail feature 129.

Two laterally opposed guide member slots 126 are formed in each of thebearing surfaces 132A, 132B. Each guide member slot 126 is a blindpocket or cavity that is open at the corresponding bearing surface 132A,132B and closed at its opposite axial end within the body 120 of thephalanx. Each guide member slot 126 has a prescribed axial depth D1(FIG. 10). According to some embodiments, the depth D1 is in the rangeof from about 20% to 50% of the axial length L2 (FIG. 10) of the phalanx110-116, and in embodiments is 40% of the axial length L2.

Each of the phalanxes 112, 114, 116 includes a lead wire bore or port128 (FIGS. 9 and 18) extending radially through the body 120 from thecentral bore 122 to the exterior of the phalanx. In embodiments, thewire port 128 of each phalanx 112, 114, 116 is angled in the radiallyinward direction toward the proximal end 100A of the phalanx (FIG. 18).This directionality assists with feeding wires from the exterior of thephalanx into the central bore 122 and down to a remote receiver 171 atthe base of the finger 100 or in the hand 20.

With reference to FIGS. 4-9, each of the vertebrae V1-V6 includes a body140, a central bore 142, an inner raceway 144A, and an outer raceway144B, a proximal bearing surface 142A, a distal bearing surface 142B,and pairs of guide member slots 146 formed in each of the bearingsurfaces 142A, 142B. The guide member slots 146 extend fully through thethickness of the vertebra and terminate at opposed slot openings at thebearing surfaces 142A, 142B. Each of the bearing surfaces 142A, 142B isnonplanar and includes an inner section 144L and an outer section 144U.The bearing surfaces 142A, 142B of the vertebrae V3-V6 also include amidsection 144M (FIGS. 4 and 5). In some embodiments, each of thesections 144U, 144L, 144M is substantially planar and is disposed at anangle to each of the other two sections.

With reference to FIGS. 3 and 10, each guide member 118 extends from aphalanx proximal bearing surface 132A to the opposing phalanx bearingsurface 132B, and through the interposed vertebrae V1-V6. The ends 118Aof each guide member 118 are slidably received in the guide member slots126 of the opposed phalanxes and extend slidably through the guidemember slots 146 of the interposed vertebrae. In some embodiments and asillustrated, the cross-sectional shapes of the slots 126, 146 aresubstantially congruent to the cross-sectional shapes of the guidemembers 118 received therein.

In other embodiments, one end 118A of each guide member 118 is secured(e.g., by adhesive, heat welding, molding or a fastener) in its guidemember slot 126 while the other end of that guide member 118 remainsslidably seated in its guide member slot 126.

With reference to FIGS. 3, 11, and 12, the inner tendon cable 156extends from a drive spool 154 and through the inner raceways 124A, 144Ato the distal phalanx 116. The outer tendon cable 158 extends from thedrive spool and through the outer raceways 124B, 144B to the distalphalanx 116. In some embodiments, each tendon cable 156, 158 includestwo parallel strands 156B, 158B (FIG. 3) connected at a closed loop156A, 158A (FIG. 12) at its distal terminal end (e.g., a singlecontinuous strand is folded 180 degrees at the distal end). The pin 149extends through the pinhole 128 and the end loops 156A, 158A to therebysecure the ends of the tendon cables 156, 158 in the distal phalanx 116.The tendon cables 156, 158 are slidably received in each of the raceways124A, 124B, 144A, 144B. Each of the raceways 124A, 124B, 144A, 144B maybe provided with rounded, flared, funnel-shaped, or radiused inlets andoutlets.

The central bores 122, 142 of the phalanxes 110-116 and the vertebraeV1-V6 collectively define or form a finger central bore 135 (FIG. 11)extending axially continuously the length of the finger 100 from thebase member 110A to the distal phalanx 116. Referring to FIG. 15, it canbe seen that the phalanxes 110, 112, 114 and 116 have bodies 120 a, 120b, 120 c and 120 d, respectively, which have central bores 122 a, 122 b,122 c and 122 d, respectively, that combine, sequentially and end toend, with one another and the central bores 142 of the vertebrae V1-V6to form the finger central bore 135.

The guide members 118 and the tendon cables 156, 158 each form parts ofthe knuckle joints JP, JM, JD. The guide members 118 couple the adjacentends of the phalanxes 110, 112, 114, 116 and the vertebrae V1-V6together at the knuckle joints JP, JM, JD. The guide members 118 and thetendon cables 156, 158 also prevent the vertebrae from falling outposition between the phalanxes. The guide members 118 and the tendoncables 156, 158 are compliant, bendable or flexible so that thephalanxes 110-116 can be relatively pivoted about the pivot axes PP-PP,PM-PM, PD-PD. As discussed below, the guide members 118 and the tendoncables 156, 158 may also permit limited bending of the finger 100 at theknuckle joints JP, JM, JD in lateral directions about sideward axesPSP-PSP, PSM-PSM, PSD-PSD (FIG. 8) that are transverse to both thefinger longitudinal axis A-A and the primary pivot axes PP-PP, PM-PM,PD-PD (FIGS. 2 and 9). As discussed below, the guide members 118 and thetendon cables 156, 158 may also permit limited twisting of the finger100 at the knuckle joints JP, JM, JD about the finger axis A-A.

According to some embodiments, the guide members 118 have a lowstiffness and low elasticity so that they do not provide substantialresistance to bending of the finger 100 at the knuckle joints JP, JM, JDand do not provide substantial return force when the finger 100 is bent.According to some embodiments, the guide members 118 have a Young'smodulus of less than 2.4 GPa at 23 degrees Celsius.

According to some embodiments, the cross-sectional shape of each guidemember 118 is rotationally asymmetric (e.g., nonsquare rectangular) sothat the guide members 118 are more compliant in one bending directionthan another. In some embodiments and as shown, the guide members 118are flat, elongate strips that have greater width in a directionparallel to the associated pivot axis PP-PP, PM-PM, PD-PD than theirthickness in a direction perpendicular to the associated pivot axisPP-PP, PM-PM, PD-PD.

According to some embodiments, the tendon cables 156, 158 have a lowstiffness and low elasticity so that, absent a tension load applied tothe tendon cables 156, 158, they do not provide substantial resistanceto bending of the finger 100 at the knuckle joints JP, JM, JD and do notprovide substantial return force when the finger 100 is bent.

According to some embodiments and as described below, a tension load ismaintained on each of the tendon cables 156, 158. As a result, thetendon cables 156, 158 draw together and apply an axially compressiveload to the phalanxes 110-116 and the vertebrae V1-V6 such that theirrespective adjacent bearing surfaces 132A, 132B, 142A, 142B are held inaxially loaded abutment when stationary and throughout their intendedranges of movement.

The phalanxes 110-116 may be formed of any suitable material(s) and maybe formed of different materials from one another. In some embodiments,the phalanxes 110-116 are formed of a polymeric material and, in someembodiments, a molded (e.g., injection molded) polymeric material.Suitable polymeric materials may include ABS, polycarbonate, nylon,acetal or PVC. According to some embodiments, the phalanxes 110-116 areformed of a material having a stiffness in the range of from about 2 to6 GPa.

The vertebrae V1-V6 may be formed of any suitable material(s) and may beformed of different materials from one another and/or different from thephalanxes 110-116. In some embodiments, the vertebrae V1-V6 are formedof a polymeric material and, in some embodiments, a molded (e.g.,injection molded) polymeric material. Suitable polymeric materials mayinclude ABS, polycarbonate, nylon, acetal or PVC. According to someembodiments, the vertebrae V1-V6 are formed of a material having astiffness in the range of from about 2 to 6 GPa.

The guide members 118 may be formed of any suitable material(s). In someembodiments, the guide members 118 are formed of a polymeric materialand, in some embodiments, a molded polymeric material. Suitablepolymeric materials may include nylon or polyurethane. According to someembodiments, the guide members 118 are formed of a material having aYoung's modulus of less than about 2.4 GPa at 23 degrees Celsius. Insome embodiments, the guide members 118 can be formed of a stiffmaterial such as spring steel that is thin or comprised of a stack ofthin members to achieve the desired flexibility.

The tendon cables 156, 158 may be formed of any suitable material(s). Insome embodiments, the tendon cables 156, 158 are formed of a polymericmaterial. Suitable polymeric materials may include ultra-high molecularweight polyethylene (UHMWPE). In some embodiments, the tendon cables156, 158 are formed of metal. Suitable metals may include carbon steelof stainless steel.

According to some embodiments, the tendon cables 156, 158 are formed ofa material having a modulus of elasticity in the range of from about 150GPa to 200 GPa. According to some embodiments, the tendon cables 156,158 are formed of a material having an ultimate tensile strength in therange of from about 2.5 GPa to 3.5 GPa.

The covers 148 may be formed of any suitable material(s). The covers 148maybe cast or injection molded. In some embodiments, the covers 148 areformed of a polymeric material. In some embodiments, the covers 148 areformed of a polymeric foam. Suitable polymeric materials may includeurethane, polyurethane, rubber, or EPDM. According to some embodiments,the covers 148 are formed of a material having a hardness in the rangeof from about 20 Shore A to 80 Shore A. According to some embodiments,the covers 148 have a thickness in the range of from about 1 mm to 6 mm.

With reference to FIGS. 2, 3 and 12, the drive system 150 includes anactuator 152, a driven gear 152A, a spool 154, and a tensioningmechanism 160. The actuator 152 may be an electric motor, for example.The driven gear 152A is connected to the output shaft of the actuator152 (e.g., via a drive gear) such that the actuator 152 can selectivelyforcibly driven the gear 152A in either rotational direction. The spool154 is connected to the driven gear 152A for rotation therewith. Acontroller associated with the robot 5 can be used to selectively drivethe spool 154 in opposed rotational directions R1 and R2 (which may bereferred to herein as clockwise and counterclockwise directions for thepurpose of explanation).

The tensioning mechanism 160 (FIGS. 2, 3 and 12) includes an innerswingarm 162A pivotally mounted on the housing 110B by a pivot pin 162B.The tensioning mechanism 160 further includes an outer swingarm 164Apivotally mounted on the housing 110B by a pivot pin 164B. An innerguide roller 162 and an outer guide roller 164 are mounted on theswingarms 162A and 164A, respectively. A torsion spring 166 is connectedto each of the swingarms 162A and 162B to bias or force the swing arms162A and 162B into or toward the relaxed positions KR as shown in FIG.11. As discussed herein, the tensioning system 160 includes a mechanismto transition the tendon cable tension from being dictated by thesprings 166 to being completely countered by the structure of thehousing 110B.

The tendon cables 156, 158 are each connected at their proximal ends tothe spool 154 to be taken up and payed out from the spool 154 as thespool 154 is rotated in either direction R1, R2. In some embodiments,the ends of the strands 156B or 158B are knotted at the distal end ofthe associated tendon cable 156, 158 and the knot is housed in the spool154.

The inner tendon cable 156 is routed from the spool 154, over theoutside of the guide roller 162, through the raceways 124A, 144A, and tothe termination pin 149. The outer tendon cable 158 is routed from thespool 154, over the outside of the guide roller 164, through theraceways 124B, 144B, and to the termination pin 149.

In a prescribed neutral position as shown in FIG. 12, the rollers 162,164 are displaced from the positions KR as shown in FIG. 11 to neutralpositions KN as shown in FIG. 12. The springs 166 are thereby displacedfrom their relaxed positions and apply a return bias or force to therollers 162, 164 and the tendon cables 156, 158. As a result, in theneutral position the springs 166 apply the tension load to the tendoncables 156, 158 to provide a persistent compressive loading on thephalanxes 110-116 and the vertebrae V1-V6.

The sensor system 170 (FIGS. 18-22) includes a proximal tactile sensorassembly 172, a medial tactile sensor assembly 174, a distal tactilesensor assembly 176, insulated electrical lead wires WP, WM, WD, and aremote receiver 171.

With reference to FIG. 19, the proximal sensor assembly 172 includessensors 172A, 172B, 172C, and 172D. The sensors 172A and 172B coverside-by-side inner, central surfaces of the proximal phalanx 112. Thesensors 172C, 172D each cover opposing adjacent side surfaces of theproximal phalanx 112.

The medial sensor assembly 174 includes sensors 174A, 174B, 174C, and174D. The sensors 174A and 174B cover side-by-side inner, central of themedial phalanx 114. The sensors 174C, 174D each cover opposing adjacentside surfaces of the medial phalanx 114.

The distal sensor assembly 176 includes sensors 176A, 176B, 176C and176D. The sensors 176A, 176B cover side-by-side proximal or main inner,central surfaces of the distal phalanx 116. The sensor 1760 covers adistal or fingertip surface of the distal phalanx 116. The sensor 176Ccovers a transitional surface of the distal phalanx 116 between the mainsurfaces and the fingertip surface.

The placements and layouts of the sensors 172A-D, 174A-D and 176A-D asdescribed above and shown in FIGS. 18 and 19 are exemplary of someembodiments. However, other placements and layouts may be employed inaccordance with embodiments of the invention. In particular, the sensorscan be distributed over the surfaces of the phalanxes 110-116 asdesired, including on the back sides of the phalanxes 110-116 and evenon the fingernail feature 129 to sense forces applied to the fingernailfeature 129.

The construction and operation of the distal sensor assembly 176 will bedescribed immediately below. However, this description generally appliesto the construction and operation of the sensor assemblies 172, 174, aswell.

With reference to FIGS. 20-22, the distal sensor assembly 176 includes asubstrate (PCB) 180, an electrically conductive layer 186, and a spacer188. The electrically conductive layer 186 may be resistive. In someembodiments, the spacer 188 is omitted.

The PCB 180 includes an inner surface 180A. The PCB 180 is divided intoa proximal PCB section 182A, a medial PCB section 182C, and a distal PCBsection 182D separated by bend or break lines 180B. According to someembodiments, the PCB 180 is rigid.

FIG. 21 illustrates the PCB 180 in greater detail. Referring to FIG. 21,an electrically conductive trace pattern 184 is provided on the innersurface 180A. The pattern 184 defines four electrically conductivetraces C1-C4, each defining a respective sensor area or sensing zoneE1-E4. The traces C1, C2, C3, and C4 each define electrical contactsthat are interdigitated with electrical contacts of a common trace CG.

The traces C1-C4 are coupled to respective electrically conductivesurface mount contact pads CP1, CP2, CP3, CP4 on the backside outersurface 180C of the PCB 180. Selection lead wires A1, A2, A3 and A4 areelectrically and mechanically terminated on or connected to the contactpads CP1, CP2, CP3 and CP4, respectively. The contact pad CPG iselectrically connected to the common trace CG by output lead wire B,which provides an input to an analog to digital converter on amicrocontroller that is off-board (not shown).

With reference to FIG. 21, the traces C1 extend across a first sensingzone or region E1 corresponding to the sensor 176A. The traces C2 extendacross a second sensing zone or region E2 corresponding to the sensor176B. The traces C3 extend across a third sensing zone or region E3corresponding to the sensor 176C. The traces C4 extend across a fourthsensing zone or region E4 corresponding to the sensor 176D.

The electrically conductive layer 186 has an electrically conductiveinner surface 186A. The sections of the conductive layer 186 overlyingthe sensing regions E1, E2, E3 and E4 form parts of the sensors 172A,172B, 172C and 172D, respectively.

The electrically conductive layer 186 is formed of a compliant, pliable,flexible, thin material. According to some embodiments, the layer 186 ismonolithic.

According to some embodiments, the layer 186 has a thickness T1 (FIG.22) in the range of from about 0.05 to 0.2 mm and, in some embodiments,from about 0.1 to 0.2 mm.

According to some embodiments, the layer 186 is a semiconductor layer.In some embodiments, the semiconductor layer 186 has a sheet resistancein the range of from about 2 kiloohms/square to 20 kiloohms/square. Insome embodiments, the semiconductor layer 186 is a polymeric filmimpregnated with an electrically conductive filler (e.g., a polyoletinor polyethylene film containing a substantially homogenous fill ofcarbon black, silver or other conductive particles). Suitable materialsfor the semiconductor layer 186 may include VELOSTAT™ film availablefrom 3M Company of Minnesota or LINQSTAT film available from CaplinqCorporation of The Netherlands.

The spacer 188 includes windows or openings 188A defined therein.According to some embodiments, the spacer 188 has a thickness T2 (FIG.22) in the range of from about 0.1 to 0.3 mm. According to someembodiments, the spacer 188 is formed of an electrically insulatingmaterial. Suitable materials for the spacer 188 may include a polymericmaterial such as polyimide film. In some embodiments, the spacer 188 isa double-sided adhesive tape.

With reference to FIGS. 18 and 20, the PCB 180, the spacer 188 and theelectrically conductive layer 186 are stacked such that the spacer 188is sandwiched or interposed between the PCB 180 and the conductive layer186 and the inner surfaces 180A and 186A face one another. The openings188A overlie the sensing regions E1-E4 so that the inner surface 180A isexposed to the inner surface 186A. The spacer 188 separates and definesa gap G between the inner surfaces 180A and 186A. According to someembodiments, the gap G has a height H3 (FIG. 22) in the range of fromabout 0.1 to 0.3 mm. The gap G may be nonexistent (i.e., H3 is zero) ifthe spacer 188 is omitted.

In use, the selection wires A1-A4 are used by the off-boardmicrocontroller, or other switching circuit, to switch between thetraces C1-C4, in sequence. A difference in resistance between thecurrently active one of the traces C1-C4 and the common trace CG (forexample, responsive to pressure on the conductive layer 186) can cause achange in the reading on the input to the microcontroller provided byoutput wire B. The sequential switching among the selection wires A1-A4may be implemented using FETs in the microcontroller's digital outputs,or even by a respective external FET for each trace C1-C4.

While embodiments of the present invention as illustrated in FIGS. 20-22are described herein with reference to an off-board microprocessor thatis configured to sequentially switch among the traces C1-C4 of therespective sensing zones E1-E4, it will be understood that otherimplementations may be used in accordance with the present invention.For example, in some embodiments, an on-board multiplexer or otherswitching circuit may be coupled between the contact pads CP1, CP2, CP3,CP4, CPG and the traces C1-C4 to control the sequential switching amongthe traces C1-C4 (i.e., a multiplexer or switching circuit may beintegrally mounted on the PCB 180 mounted on the finger phalanx). Suchan embodiment may likewise include five wires extending from the outersurface 180C of the PCB 180: a power wire, a ground wire, two selectline wires (for selecting among the four traces C1-C4), and an analogoutput wire. Alternatively, in other embodiments, each of the fourtraces C1-C4 may have its own dedicated selection line wire and outputline wire, resulting in a total of eight wires extending from the outersurface 180C of the PCB 180.

Also, although illustrated with reference to a single, continuousconductive film 186, it will be understood that the conductive film 186may alternatively be divided into multiple, isolated sections (forexample, corresponding to each of the sensing zones E1-E4), which mayreduce or eliminate contributions from zones other than the selectedzone in the output.

The finger 100 may be assembled as follows in accordance withembodiments of the invention. The modular design of the finger 100permits assembly without special equipment or skill.

The distal sensor assembly 176 is mounted on the exterior of the distalphalanx 116 such that the PCB 180 is interposed between the phalanx 116and the conductive layer 186 (i.e., the conductive layer 186 is on theoutwardly facing ride of the sensor assembly 176). The PCB 180 may beaffixed to the phalanx 116 by adhesive, for example. The sensors176A-176D overlie the main, transitional and fingertip surfaces of thephalanx as discussed above. As shown in FIGS. 18 and 19, the sections182A-182D of the PCB 180 follow the contour of the fingertip of thedistal phalanx 116 so that the sensors 174C and 174D are disposed at anangle with respect to each other and the sensors 174A, 174B.

The lead wires A1-A4, 13 (generally referred to herein and designated inFIG. 18 as lead wires WD) from the sensor assembly 176 are routed intothe central bore 122 of the phalanx 116 through the wire port 128. Forclarity, only two lead wires WD are illustrated in FIG. 18; however, inpractice there will be five lead wires WD extending through the centralbore 122. The angled geometry of the wire port 128 directs the leadwires WD toward the proximal end of the phalanx 116. Lengths of the leadwires WD extend out from the phalanx 116. The cover 148 is mounted overthe phalanx 116 and the sensor assembly 176.

Two guide members 118 are inserted into the guide member slots (pockets)126 of the distal phalanx 116. The vertebrae V5, V6 are then mounted onthe subassembly such that the guide members 118 extend through the guidemember slots 146 of the vertebrae V5, V6 and the wires WD extend throughthe central bores 142 of the vertebrae V5, V6.

The medial sensor assembly 174 is mounted on (e.g., affixed by adhesiveto) the exterior of the medial phalanx 114 such that the PCB 180 isinterposed between the phalanx 114 and the conductive layer 186. Thesensors 174A-1740 of the medial sensor assembly 174 overlie the main andlateral side surfaces of the phalanx 114 as discussed above and shown inFIGS. 18 and 19.

In some embodiments, the sensors 172A-D, 174A-D, 176A-D are affixeddirectly to the outer surfaces of the phalanxes 110-116. Mounting thesensors in this manner can provide a number of advantages. Such mountingcan provide more sensitive sensor response and can permit a morestreamlined finger with more accurate dexterity.

The lead wires WM from the sensor assembly 174 are routed into thecentral bore 122 of the phalanx 114 through the wire port 128. Forclarity, only two lead wires WM are illustrated in FIG. 18; however, inpractice there will be five lead wires WM extending through the centralbore 122. The angled geometry of the wire port 128 directs the leadwires WM toward the proximal end of the phalanx 114. Lengths of the leadwires WM extend out from the phalanx 114. The cover 148 is mounted overthe phalanx 114 and the sensor assembly 174.

This subassembly is then mounted on the foregoing subassembly ofcomponents 116, 176, 148 such that the lead wires WD extend through thebore 122 of the medial phalanx 114 and out beyond the proximal end ofthe phalanx 114. The proximal ends of the guide members 118 are insertedinto the distal end guide member slots 126 of the medial phalanx 114.

Two guide members 118 are seated in the guide member slots 126 (proximalside) of the medial phalanx 114. The vertebrae V3, V4 are then mountedon the foregoing subassembly such that the guide members 118 extendthrough the guide member slots 146 of the vertebrae V3, V4 and the wiresWD, WM extend through the central bores 142 of the vertebrae V3, V4.

The proximal sensor assembly 172 is mounted on (e.g., affixed byadhesive) the exterior of the proximal phalanx 112 such that the PCB 180is interposed between the phalanx 112 and the conductive layer 186. Thesensors 172A-172D of the proximal sensor assembly 172 overlie the mainand lateral side surfaces of the phalanx 112 as discussed above andshown in FIG. 19.

The lead wires WP from the sensor assembly 172 are routed into thecentral bore 122 through the wire port 128. For clarity, only two leadwires WP are illustrated in FIG. 18; however, in practice there will befive lead wires WP extending through the central bore 122. The angledgeometry of the wire port 128 directs the lead wires WP toward theproximal end of the phalanx 112. Lengths of the lead wires WP extend outfrom the phalanx 112. The cover 148 is mounted over the phalanx 112 andthe sensor assembly 172.

This subassembly is then mounted on the foregoing subassembly ofcomponents 116, 176,114, 174, 148 such that the lead wires WD, WM extendthrough the bore 122 of the proximal phalanx 112 and out beyond theproximal end of the phalanx 112. The proximal ends of the guide members118 are seated in the distal end guide member slots 126 of the proximalphalanx 112. It will be appreciated that at this time a bundle of thelead wires WD, WM, WP extends from the proximal end of the proximalphalanx 112.

Two guide members 118 are seated in the guide member slots 126 (proximalside) of the proximal phalanx 112. The vertebrae V1, V2 are then mountedon the foregoing subassembly such that the guide members 118 extendthrough the guide member slots 146 of the vertebrae V1, V2 and the wiresWD, WM, WP extend through the central bores 142 of the vertebrae V1, V2.

The base member 110A is then mounted on the foregoing subassembly ofcomponents 116, 176, 114, 174, 112, 172, 148 such that the lead wiresWD, WM, WP extend through the bore 122 of the base phalanx 110 and outbeyond the proximal end of the base phalanx 110. The proximal ends ofthe guide members 118 are seated in the distal end guide member slots126 of the base phalanx 110. At this time the bundle of lead wires WD,WM, WP extends from the proximal end of the base phalanx 110 and intothe housing 110B. It will be appreciated that the phalanxes 110, 112,114, 116 and the vertebrae V1-V6 are now loosely and slidably coupledtogether and rotationally and laterally aligned by the guide members118.

The tendon cables 156, 158 are then installed and secured in the finger100. The inner tendon cable 156 is inserted from the proximal end of thebase phalanx 110 and serially through the inner raceways 124A, 144A ofthe phalanxes 112-116 and vertebrae V1-V6 until the end loop 156A ispositioned at the pinhole 128, as shown in FIG. 12. The outer tendoncable 158 is inserted from the proximal end of the base phalanx 110 andserially through the outer raceways 124B, 144B of the phalanxes andvertebrae until the end loop 158A is positioned at the pinhole 128, asshown in FIG. 12. The pin 149 is then inserted into the pinhole 128 andthrough the end loops 156A, 158A and secured in place to thereby anchorthe tendon cables 156, 158. The proximal ends of the tendon cables 156,158 are secured to the spool 154 from opposite sides.

The robotic end effector 10 and finger 100 may be used as follows inaccordance with embodiments of the invention. The fingers 100, 102, 104,106 may each be operated to bend into open and closed positions asdescribed below. The fingers 100-106 may be operated independently ofone another. The fingers 100-106 may be operated cooperatively toexecute desired actions such as grasping. Operation of the finger 100will be described in detail hereinbelow. However, it will be appreciatedthat this description likewise applies to the fingers 102, 104, 106.

Initially, the spool 154 of the finger 100 may be set to a neutralposition thereby causing the finger 100 to assume a prescribed neutralposition as shown in FIGS. 1, 2 and 12. In some embodiments, the finger100 is curved in the neutral position to emulate the posture of arelaxed human finger. In the neutral position, the phalanxes 112, 114,116 and the vertebrae V3-V6 abut on their respective planar midsections134M, 144M. In some embodiments, in the neutral finger position theinner tendon cable 156 and the outer tendon cable 158 are undersubstantially the same tension absent the application of an externalload.

As shown in FIG. 12, the guide rollers 162, 164 are displaced to theirneutral positions KN. As a result, the deflected springs 166 arepreloaded and apply a persistent spring force or preload to the tendoncables 156, 158 tending to pull the tendon cables 156, 158 in theproximal direction. In the neutral position, the finger 100 assumes aprescribed pose as shown in FIG. 12 and discussed below. The persistentpreload tension on the tendon cables 156, 158 acts to exert an axiallycompressive force on the phalanxes 110-116 and the vertebrae V1-V6.

From the neutral position of the finger 100, the phalanxes 112-116 canbend about the pivot axes PP-PP, PM-PM, PD-PD at the knuckle joints JP,JM, JD in both a closing direction MC and an opening direction MO (FIG.12).

In order to bend the finger 100 in the closing direction MC, the spool154 is driven by the actuator 152 to rotate in the counterclockwisedirection R2. As a result, the inner tendon cable 156 is wound onto thespool 154 and the outer tendon cable 158 is payed out from the spool 154so that the length of the inner tendon cable 156 (between the spool 154and the pin 149) is reduced and the length of the outer tendon cable 158(between the spool 154 and the pin 149) is increased. The springs 166continue to be deflected and exert positive tension on the tendon cables156, 158. However, when the finger 100 encounters resistance (e.g., isexerting a force on an encountered object) or reaches its maximum closedposition (as shown in FIG. 13), the tension on the inner tendon cable156 will exceed that of its neutral position, and the tension on theouter tendon cable 158 may be less than that of its neutral position, sothat the rollers 162, 164 are deflected to new positions KCI and KCO,respectively, as shown in FIG. 13.

In order to bend the finger 100 in the opening direction MO, the spool154 is driven by the actuator 152 to rotate in the clockwise directionR1. As a result, the outer tendon cable 158 is wound onto the spool 154and the inner tendon cable 156 is payed out from the spool 154 so thatthe length of the outer tendon cable 158 (between the spool 154 and thepin 149) is reduced and the length of the inner tendon cable 156(between the spool 154 and the pin 149) is increased. The springs 166continue to be deflected and exert positive tension on the tendon cables156, 158. However, when the finger 100 encounters resistance (e.g., isexerting a force on an encountered object) or reaches its maximum openposition (as shown in FIG. 14), the tension on the outer tendon cable158 will exceed that of its neutral position, and the tension on theinner tendon cable 156 may be less than that of its neutral position, sothat the rollers 162, 164 are deflected to new positions KOI and KOO,respectively, as shown in FIG. 14.

According to some embodiments, the tendon cables 156, 158 are relativelylightly preloaded by the tensioning system 160 in the neutral position.The springs 166 have a progressive spring force/spring deflection curveso that when the finger 100 encounters resistance and the roller 162,164 of the pulling tendon cable 156 or 158 is displaced, the load onthat tendon cable gradually increases or ramps up. Once the associatedroller 162, 164 is fully extended (i.e., has been deflected to itsforwardmost available position), the full tendon force will be exertedindependent of the spring 166. That is, when the swingarms 162A, 164Aare deflected away from the distal end 110B of the finger 100, thetension in the tendon cables 156, 158 is dictated by the spring preload.However, as the tendon tension increases, the swingarms 162A, 164A arepulled towards the distal end 110B and slowly transition the tensionfrom the spring 166 to the structure of the housing 110B. For example,even if the spring 166 were omitted, the maximum tendon tension wouldstill be supported as the swingarms 162A, 164A become effectivelytwo-force members.

Thus, both movement and restoring force are provided via the tendoncables 156, 158. The tensioning system 160 and the tendons 156, 158serve as a suspension system for the finger 100. The tensioning system160 can ensure that the tendon cables 156, 158 are maintained taut anddo not acquire slack throughout the intended range of motion of thefinger 100. In some embodiments, the tensioning system 160 maintains apositive tension on the tendon cables 156, 158 at all times.

According to some embodiments, the preload force on the tendon cables156, 158 in the neutral position is in the range of from about 3 lbs to10 lbs. Higher preloads may be achieved using stronger springs; however,tendon life is extended or maximized by minimizing the nominal preload.

As discussed above, the finger 100 bends at the knuckle joints JP, JM,JD. The knuckle joints JP, JM, JD can thus provide hinge-like movementbetween the phalanxes 110-116. The flexible coupling by the guidemembers 118 and the tendon cables 156, 158 permits the adjacent bearingsurfaces 132A, 132B, 142A, 142B of the phalanxes 110-116 and thevertebrae V1-V6 to rotate, roll or pivot relative to one another. Thepositioning of tendon cables 156, 158 and the preferential bending shapeof the guide members 118 inhibits relative displacement between thephalanxes and vertebrae out of the prescribed bending plane (i.e., theplane normal to the pivot axes PP-PP, PM-PM, PD-PD).

The axially compressive loading by the tensioning mechanism 160 tends tomaintain the adjacent bearing surfaces 132A, 132B, 142A, 142B in contactwith one another throughout the rolling movement. The guide members 118laterally and rotationally center the vertebrae and phalanxes of eachknuckle joint. The guide members 118 are able to slide in and out of theguide member slots 126, 146 as the distance between the phalanxes andthe vertebrae vary through the finger's range of motion. In this manner,the guide members 118 can accommodate the free movement of the phalanxesand the vertebrae while still providing guidance and stability to thephalanxes and the vertebrae.

The lengths of the guide members 118 and the depths of the slots 126(and thereby the insertion depths of the guide members 118 into theslots 126 and the range of movement therein) are selected to ensure thatthroughout the range of motion of the finger 100 the ends 118A of theguide members 118 will not pull fully out of their slots 126. Accordingto some embodiments, the guide members 118 do not significantly stretchaxially throughout the range of motion of the finger 100.

In some embodiments and as illustrated, the finger 100 is shortest wheneach joint JP, JM, JD is in its neutral state (FIG. 12), and the guidemember slots 126, 146 should be sufficiently deep that the guide members118 do not “bottom out” guide member slots 126, 146 while in this state.As the joint JP, JM, JD deflect, the finger 100 lengthens, thusrequiring that the guide members 118 be able to slide relative to thephalanxes and vertebrae.

Because the loads on each joint JP, JM, JD increase from the distal endto the proximal end, the required cross-section of the guide members 118also increases. In some embodiments and as illustrated, the guidemembers 118 of each joint increase from the distal joint JD to theproximal joint JP.

In other embodiments, each guide member 118 may be affixed to one (andonly one; i.e., exactly one) of the finger joint components, either oneof the phalanxes 110-116 or one of the vertebrae V1-V6 forming a part ofthe respective joint, as long as the guide member 118 can still sliderelative to the remaining joint components. In embodiments, each guidemember 118 may be molded integral to one of the finger joint components,one of the phalanxes 110-116 or one of the vertebrae V1-V6 forming apart of the respective joint, to further reduce cost and assembly labor.

According to further embodiments, two or more (e.g., all) of the guidemembers 118 that run the length of the finger 100 on a given side may becombined into a single molded part constituting a multi joint guidemember. This multi joint guide member may decrease in cross-section asit extends from the proximal end towards the distal end of the finger100. This multi joint guide member may be affixed to or moldedintegrally with one of the finger joint components (i.e., one of thephalanxes 110-116 or one of the vertebrae V1-V6) or may be held captivein guide member slots in the same manner as the guide members 118.

During an “overload” event, the joints JP, JM, JD may be pulled evenfurther apart than they will be during their standard range of motion.The lengths of the guide members 118 should be sufficient to accommodatethis amount of separation so that the joints JP, JM, JD can be separatedyet still reseat when the overload is relieved.

Referring to FIG. 12, it can be seen that in the illustrated neutralposition the mating faceted bearing surfaces 132A, 132B, 142A, 142B ofeach of the phalanxes 110-116 and the vertebrae V1-V6 engage each otherat their respective midsections 134M, 144M. The geometries of thebearing surfaces 132A, 132B, 142A, 142B and the lengths of the tendoncables 156, 158 are configured to achieve this finger configuration whenthe tendon cables 156, 158 are adjusted to the neutral position lengthsand no external force or resistance is applied. Notably, gaps arepresent between the opposing bearing surfaces 132A, 132B, 142A, 142Bboth above and below their mating points.

With reference to FIG. 13, when the spool 154 is rotated in thecounterclockwise direction R2 to close the finger 100, the bearingsurfaces 132A, 132B, 142A, 142B will roll counterclockwise about oneanother to reduce the lower gaps, thereby curling the phalanxes 110-116and the vertebrae V1-V6 downwardly or inwardly. The finger 100 may becurled inwardly in this manner until the opposing lower sections 134L,144L of the bearing surfaces abut and act as mechanical stop faces thatprevent or limit further rotation. The proximal joint JP will bendbefore the middle joint JM and the distal joint JD and will reach itsmaximum position before the joints JM, JD bend unless the fingerencounters an external force or object.

With reference to FIG. 14, when the spool is rotated in the clockwisedirection R1 to open the finger 100, the bearing surfaces 132A, 132B,142A, 142B will roll clockwise about one another to reduce the uppergaps, thereby curling the phalanxes 110-116 and the vertebrae V1-V6upwardly or outwardly. The finger 100 may be curled outwardly in thismanner until the opposing upper sections 134U, 144U of the bearingsurfaces abut and act as mechanical stop faces that prevent or limitfurther rotation. Again, the proximal joint JP will bend to its maximumposition prior to displacement of the joints JM, JD unless the fingerencounters an external force or object.

The prescribed geometries of the phalanxes 110-116 and the vertebraeV1-V6, including their bearing surfaces 132A, 132B, 142A, 142B, willdetermine, prescribe, set or dictate the shape of the finger 100 at anygiven position in its range of movement. The selection or modificationof these geometries can be used to design or tune the performance of thefinger 100. The geometries may be selected to determine a shape of thefinger 100 and/or a bending sequence. For example, the finger 100 may beredesigned to assume a less tight position when fully closed. In theillustrated configuration, when the spool 154 is rotated to close thefinger 100, the finger 100 will bend first at the proximal knuckle jointJP and then at the knuckle joints JM, JD after the finger 100 hasreached the limit of the proximal joint JP or the finger encounters anexternal force or object. Due to inherent frictional losses in thetendons 156, 158, it may only be possible to approximately control theshape of the finger 100, as it moves through its range of motion. Thisshape may also differ depending on the direction the finger 100 ismoving.

The proximal vertebrae V1, V2 do not have distinct flat faces betweenthe respective inner and outer sections 144U, 144L. This allows theproximal joint JP to act in a simple hinge-like manner such that theproximal joint JP swings through its entire range of motion while themore distal joints JM, JD remain in their neutral positions. In someembodiments and as illustrated in FIG. 7, each bearing surface 142A,142B of the proximal vertebrae V1, V2 has a rounded transition corner orsurface 144R between its inner and outer sections, or stop faces, 144L,144U that allows the vertebrae V1, V2 and associated phalanx bearingsurfaces 132A, 132B to roll on one another.

In some embodiments and as shown in FIG. 8, the inner section 144L andthe outer section 144U of each vertebra V1-V6 are disposed at an obliqueangle Q1 with respect to one another. The central or midsection 144M ofeach vertebra V3-V6 is disposed at an oblique angle to the sections 144Land 144U of the vertebra.

In some embodiments and as shown in FIG. 12, when the knuckle joints JM,JD are extended to their neutral positions, the opposing inner sections144L of the vertebrae V3-V6 are disposed at angles Q2 with respect toone another. According to some embodiments, each angle Q2 is in therange of from about 25 to 35 degrees.

In some embodiments and as shown in FIG. 13, when the knuckle joint JPis in its neutral position, the opposing inner sections 144L andopposing outer sections 144U of the vertebrae V1, V2 are disposed at anangle Q3 with respect to one another. According to some embodiments,each angle Q3 is in the range of from about 15 to 25 degrees.

Each of the vertebrae V1-V6 has an axial thickness T1 (FIG. 4) extendingalong the finger axis A-A, and a lateral width W1 (FIG. 5) extendingperpendicular to the finger axis A-A. The lateral width W1 of eachvertebra V1-V6 is greater than its axial thickness T1.

According to some embodiments, the lateral width W1 of each vertebraV1-V6 is at least 1.5 times its axial thickness T1, in some embodiments,at least 2 times its axial thickness, and, in some embodiments, in therange of from about 2 to 5 times its axial thickness T1. In embodiments,the ratio of lateral width W1 to axial thickness T1 increases by afactor of at least 1.25 for each knuckle joint JP, JM, JD in a directionascending from the proximal end 100A of the finger 100.

Referring to FIG. 4, the thinnest part of the vertebra (as its bottom orinner edge) must be thick enough to maintain the strength necessary tosupport the peak tendon loads without failing; the angles of the lowersurfaces (144L) then dictate how thick the vertebra becomes as itthickest end. Increasing the number of vertebrae in a given jointdecreases the angle of surfaces 144 and thus also decreases the maximumthickness T1. In embodiments, each finger joint JP, JM, JD includes atleast two vertebrae and the axial thickness T1 ranges from 2 to 6 timeslarger than the thinnest part of the vertebra. In embodiments, axialthickness T1 is four times larger than the axial thickness T8 (FIG. 4)of the thinnest part 1441 of the vertebra V4 and each lower surface 144Lis angled inward at a slope or angle Q5 (FIG. 4) in the range of 30 to55 (e.g., 35, 40, 45, 50) degrees from the plane of the adjacent uppersurface 144U.

The axial length L2 (FIG. 9) of each phalanx 112-116 is greater than theaxial thickness T1 of each vertebra V1-V6. According to someembodiments, the axial length L2 of each phalanx 112-116 is at least 2times the axial thickness T1 of each adjacent vertebra V1-V6 and, insome embodiments, in the range of from about 2 to 4 times the axialthickness T1 of each adjacent vertebra V1-V6. The main constraint on thelength L2 of each phalanx 110-116 is the desired overall length of thefinger 100. By reducing the axial thicknesses T1 of the vertebrae V1-V6,the axial lengths of the knuckle joints JP, JM, JD can be reduced orminimized, thereby permitting longer phalanxes 110-116. Longer phalanxesare desirable in order to provide adequate room thereon to accommodatesensors.

According to some embodiments, at least some of the vertebrae V1-V6 havedifferent the axial thicknesses T1 from one another. In someembodiments, the axial thicknesses T1 of the vertebrae V5, V6 are lessthan the axial thicknesses T1 of the vertebrae V3, V4.

Each of the vertebrae V1-V6 has a height H1 (FIG. 4) perpendicular toeach of its axial thickness T1 (FIG. 4) and its lateral width W1 (FIG.5), and the axial thickness T1 varies across the height H1 of thevertebra. For example, as can be seen in the side elevational view ofFIG. 4, the axial thickness T1 of the vertebra V4 varies from the inneror lower end of the vertebra V4 to the outer or upper end of thevertebra V4. The lower section of the vertebra V4 (i.e., between thesections 144L) is tapered or wedge-shaped and thus has a constantlyvarying or non-uniform axial thickness and the upper section (i.e.,between the sections 144U) is substantially uniform in axial thickness.

The provision of multiple vertebrae V1-V6 allows for larger joint anglesto be achieved, for smaller gaps between the vertebrae for a given jointangle (which creates smaller pinch points), and more gradual tendonpaths when the finger is fully deflected.

By providing multiple vertebrae in each knuckle joint, the minimum bendradius assumed by each tendon cable 156, 158 can be reduced. Forexample, with reference to FIG. 13, in the fully closed position thevertebrae V3, V4 introduce steps across the knuckle joint JM that arespanned by sections of the tendon cable 156, which are arranged atrelatively large angles to one another. In the absence of the vertebraeV3, V4, the tensioned tendon cable 158 would extend straight from thephalanx 114 to the phalanx 116 with tight angle bends where the tendoncable 158 exits the phalanxes 114, 116. This improved cable managementcan extend the service lives of the tendon cables, reduce frictionbinding, and provide smoother bending movement of the finger. Enabling agradual and non-vibrational bending of the finger allows a robot handhaving more than one of these fingers to carefully align with andposition around breakable or easily spilled objects (like coffee cupsand jugs of milk) for secure lifting without spillage or breakage.

The tensioning system 160 and the vertebrae V1-V6 can provide severaladditional advantages or beneficial performance characteristics in use.

As discussed above, the tensioning system 160 allows the tensions in thetendon cables 156, 158 to smoothly transition from a predeterminedpreload (dictated by the selected spring 166) to a state where infiniteor unlimited tension (up to the tension capacity of the tendon cable,short of breakage) can be achieved on the tendon cable regardless of theinitial preload. Accordingly, the tendon cables 156, 158 ultimatelyexert the full force of the actuator 152 but only a relatively smallinitial preload tension need be provided on the tendon cables 156, 158to prevent the tendon cables 156, 158 from ever becoming slack in theoperating range. This lower preload tension in the neutral position andfor light loads can reduce tendon cable stretch and minimize tendoncable friction to extend the service life of the tendon cables.Minimizing tendon cable friction reduces the energy and output capacityrequirements for the actuator 152.

The tensioning system 160 accommodates stretch of the tendon cables 156,158 over time. The tensioning system 160 eliminates the need for amanual tensioning mechanism, thereby eliminating the risk of manualerror and reducing service costs.

In embodiments in which the overall tendon length is variable, thetensioning system 160 accommodates tendon cable paths that are not equallength over the range of motion. The tensioning system 160 and drivesystem 150 allow for equal bidirectional performance so that eithertendon 156, 158 can be activated depending on the direction of motiondesired. The tensioning system 160 does not require the spool 154 tofloat. The tensioning system 160 can thus allow greater flexibility inthe design of the drive system and a smaller form factor.

The tensioning system 160 and the vertebrae V1-V6 also enable the finger100 to absorb external forces, impacts or shocks without damage. Forexample, with reference to FIG. 15, when an upward force IU is incidenton the finger 100 tending to force the finger open, the force isabsorbed by the spring 166 of the roller 162. The roller 162 is therebydeflected to an extended position KUI. Additionally, the roller 164 ispulled back to a retracted position KUO by its spring 166, therebypreventing slack in the tendon cable 158. When the external force isreleased, the spring 166 of the roller 162 will force the rollers 162,164 and the finger 100 back to their original positions. Notably, thetendon tension never encounters an “step-change” in tension (like wouldhappen if the tensioner were to encounter a mechanical stop) which canlead to catastrophic failure of the tendon. The physics of thetensioning system 160 gradually increase the tendon tension from thespring preload up to whatever force is necessary to counter the load.

Similarly, with reference to FIG. 16, when a downward force ID isincident on the finger 100 tending to force the finger closed, the forceis absorbed by the spring 166 of the roller 164. The roller 164 isthereby deflected to an extended position KDO. Additionally, the roller162 is pulled back to a retracted position KDI by its spring 166,thereby preventing slack in the tendon cable 156. When the externalforce is released, the spring 166 of the roller 164 will force therollers 162, 164 and the finger 100 back to their original positions.

The tensioning system 160 can also accommodate laterally directedexternal loads. With reference to FIG. 17A when a sideward or lateralforce IS (e.g., into or out of the plane of the paper in FIG. 17) isincident on the finger 100 tending to force the finger to bend sidewaysabout bend axes PSP-PSP, PSM-PSM, and/or PSD-PSD (FIG. 8), the force isabsorbed by the springs 166 of both the roller 162 and the roller 164.The rollers 162, 164 are thereby deflected to extended positions KS.When the external force is released, the springs 166 will force therollers 162, 164 and the finger 100 back to their original positions.

The tensioning system 160 can be particularly beneficial when theexternal force is a shock, impact force or impulse load. In this case,the springs 166 can absorb, damp, dissipate or ramp the impact load toprotect the tendon cables or other components of the finger 100. Thetensioning system 160 provides overload protection (such as from animpact) by ramping tension in the tendon cables up to full capacity, asopposed to creating a step change in the tension. By providing thisoverload protection, the tensioning system 160 can permit the use oftendon cables 156, 158 that themselves have very little give orelasticity. The tensioning system 160 will maintain the tendon cables156, 158 taut so that the impact does not induce slack in the tendoncables.

The tensioning system 160 and knuckle joints JP, JM, JD can alsoaccommodate torsional loads and impacts on the finger 100, such asforces tending to twist or rotate the phalanxes 110-116 about the fingeraxis A-A relative to one another. Because the guide members 118 andtendon cables 156, 158 are compliant and axially extendable bydisplacement of the rollers 162, 164 and the phalanxes 110-116 andvertebrae V1-V6 are not rigidly coupled, the phalanxes 110-116 andvertebrae V1-V6 can rotate on their bearing surfaces 132A, 132B, 142A,142B. The degree of torsional compliance can be determined by selectionof the geometry of the bearing surfaces 132A, 132B, 142A, 142B and/orthe openings of the raceways 124A, 124B, 144A, 144B (FIGS. 3, 6 and 7)and/or the guide member slots 126, 146 (FIGS. 3, 6 and 7).

The torsional compliance may be different for different knuckle jointsJP, JM, JD or for different parts within a knuckle joint. For example,the knuckle joint JM may be configured to provide a greater range oftorsional compliance than the knuckle joint JP by making the openings ofthe raceways 124A, 124B, 144A, 144B and/or the guide member slots 126,146 of the knuckle joint JM larger and more rounded (e.g., funnelshaped) than the openings of the raceways 124A, 124B, 144A, 144B and/orthe guide member slots 126, 146 of the knuckle joint JP. Such anarrangement may be desirable for executing a pinching grip maneuverusing the finger 100. According to some embodiments, the knuckle jointsJM and JD each have a torsional compliance (to the point of maximumextension of the tensioning mechanism 160) in the range of from about+/−10 degrees to +/−35 degrees from the neutral position. The amount oftorsional compliance in each knuckle joint can be increased by providingthe knuckle joint with more vertebrae. On the other hand, if reduced orzero torsional compliance is desired, cooperating shear key features canbe added to the mating surfaces of the vertebrae to limit or prevent anytorsional displacement.

As discussed above, the tensioning mechanism 160 transitions tendontension from being determined by the springs 166 to being completelycountered by the rigid structure of the housing 110B. This transitionwill occur both when the finger 100 is driven and reaches its limit(e.g., fully open position (FIG. 14) or fully closed position (FIG.13A)) or encounters an external object or force, and when the finger 100is loaded by an external force or impact (e.g., an overload impact asillustrated in FIGS. 15, 16, 17A and 17B). In these events, above athreshold tension, the swingarms 262A, 264A will assume a maximum loadposition or two-force member position.

For example, in FIGS. 13A, 15 and 17B, the swingarm 262A is shown in itsmaximum load, fully extended, or two-force member position. In FIGS. 14,16 and 17B, the swingarm 264A is shown in its maximum load, fullyextended, or two-force member position. FIG. 13B is an enlarged detailview of the swingarm 162A in its maximum load position. In the maximumload position, the swingarm 162A is positioned (“fully extended”) suchthat the associated tendon cable 156 has adopted its shortest possiblepath from the spool 154 to the exit port of the chamber housing theswingarm 162A. Any additional tension on the tendon cable 156 istherefore applied directly to the housing 110B through the swingarmpivot 162B and along an axis E-E defined by the roller pivot 162R andthe swingarm pivot 162B. Additional tension cannot be transferred to thespring 166 because the geometry of the tensioning system 160 does notpermit further rotation of the swingarm 162A. In this position, thetension force F_(T) applied to the roller 162 by the tendon cable 156and the reaction force F_(R) extend coaxially along the axis E-E throughthe pivots 162B, 162R. It will be appreciated that the tension forceF_(T) is the resultant force from or combination of the forces appliedby the two tendon cable segments extending from either side of theroller 162.

In the maximum load position, the swingarm 162A effectively becomes atwo-force member in that any additional cable tension does not alter theequilibrium position of the swingarm 162A. The tendon forces result in apure tension load being applied to the swing-arm 162A (assuming theforce applied by the spring 166 is negligible by comparison).

As the finger 100 is returned to its centered position by the tensioningsystem 160, the guide members 118 can help guide the phalanxes andvertebrae into their corresponding positions. The phalanxes andvertebrae may slide along the guide members 118 like beads on a string.The lengths of the guide members 118 and the depths of the slots 126(and thereby the insertion depths of the guide members 118 into theslots 126 and the range of movement therein) are selected to ensure thatthroughout the range of permitted displacement of the finger 100 theends 118A of the guide members 118 will not pull fully out of theirslots 126. That is, throughout the range of movement of the finger 100,the guide member ends 118A of each guide member 118 remain slidablycaptured in their slots 126 and the length of the guide member 118extending between the two slots 126 can vary to accommodate relativedisplacement between the bearing surfaces 132A, 132B, 142A, 142B withinwhich the two slots 126 are formed.

The tensioning system 160 in combination with the vertebrae V1-V6 canprovide enhanced or additional flexibility and overload protection forthe finger 100 and the actuator 152. Each of the vertebrae V1-V6provides an additional, passive degree of freedom that can be exploitedby an applied force sufficient to displace one or both of the springs166 (until the corresponding roller(s) 162, 164 is/are fully extended).The finger 100 is able to move a substantial amount and in a great manydirections even though the lengths of the tendon cables 156, 158 (asmeasured from the spool 154 to the pin 149) remain fixed. The phalanxesand vertebrae can separate from one another and will be readily returnedto their proper positions by the tensioning system 160 and the guidemembers 118.

According to some embodiments, the tensioning system 160 is configuredto permit a maximum displacement of each tendon cable 156, 158 from itsneutral position in the range of from about 4 to 8 mm.

According to some embodiments, the springs 166 each have a springconstant in the range of from about 0.02 to 0.04 in-lbs/degree.

In use, the sensor assemblies 172, 174, 176 can serve as contact ortactile sensors. As discussed above, the sensor system 170 employs anumber of distinct spatial sensing sections or regions. The sensorsystem can thus be used to detect and distinguish between application ofpressure or forces to each of these sections to provide improved, higherresolution tactile feedback for use in guiding and operating the endeffector 10. The segregation of the trace pattern 184 into multiplediscrete sensing zones can avoid or reduce stray currents through thebulk of the conductive layer 186. The sensor system 170 can also providefeedback indicating the magnitude and/or area of the applied force.

With reference to FIGS. 18-22, operation of the sensor assembly 176 willnow be described. However, it will be appreciated that this descriptionlikewise applies to the sensor assemblies 172, 174.

With reference to FIG. 22, when a sufficient force F is applied to thecover 148 over the sensor 176A, for example, in the sensing region E1,the cover 148 and conductive layer 186 are thereby deflected or deformedtoward the inner surface 180A. The inner surface 186A of the conductivelayer 186 makes contact with and bridges the conductive traces C1 andCG. The traces C1, CG are thereby electrically connected to one anotherthrough the conductive layer 186, reducing the electrical resistanceacross the sensor circuit in zone E1 and the contact pads CP1 and CPC,and thereby the corresponding lead wires A1 and B. The remote receiver171 is connected to the lead wires A1 and B and includes a suitablecircuit to measure the resistance of the sensor circuit. For example,the remote receiver 171 may include a voltage divider circuit pairedwith an analog-to-digital convertor (ADC) and a power supply providingcurrent to the sensor circuit.

According to some embodiments, the electrical resistance across thesensor circuit varies as a function of the applied force. The electricalresistance is proportional to the applied force. In particular,according to some embodiments, the sensors 176A-176D (and likewise thesensors 172A-172D and 174A-174D) are resistive sensors. As discussedabove, in some embodiments, the conductive layer 186 is a semiconductorlayer (e.g., VELOSTAT™ layer) having an inherent surface resistivity.The resistance through the conductive layer 186 is a function of thesurface resistivity and the contact area. The resistance of each sensor176A-176D will decrease in response to a greater magnitude of appliedpressure. The resistance of the sensor 176A-176D may also decrease inresponse to a greater area of applied pressure. The decrease inresistance may result from a greater collective area of contact betweenthe conductive layer 186 and the traces (e.g., traces C1 and CG) and/ora greater compressive deformation of the thickness of the conductivelayer 186 (attributable to change in the bulk (volumetric) resistivityof the conductive layer 186).

The spacer 188 and the gap G formed thereby can provide performanceadvantages by providing an open circuit when no force is applied. Thegap G can eliminate the incidence of an uncontrolled resistance atzero-force, which may occur when the conductive layer 186 is permittedto contact the traces C1, CG when no force is applied. In this way, thesensor assembly 176 can provide momentary switch action or response.After the gap G is closed, the resistance of the sensor circuit may varyas a function of the magnitude of the applied force so that changes inforce can still be detected even after the momentary switch has beenactuated. In some embodiments, the spacer 188 and the gap G may beomitted so that the sensor assembly 176 can more effectively detectsmall initial applied forces without the momentary on/off switch effect.

As discussed above, the sensor assembly 176 includes four sensors176A-176D each corresponding to a respective sensing region E1-E4 andeach having a respective trace C1-C4 and a common trace CG. By cyclingthrough the contact pads CP1-CP4, the sensor assembly 176 seriallysamples or provides the remote receiver 171 with electrical resistancesfrom each of the four sensors 176A-1760 and sensing regions E1-E4.

The sensor assemblies 172, 174 may be used in the same manner asdescribed above for the sensor assembly 176. Each sensor assembly 172,174 may similarly include multiple sets of traces, multiple discretesensors 172A-172D, 174A-174D and sensing regions, and a switchingcircuit that cycles through the sensors 172A-172D, 174A-174D. Forexample, the sensor assembly 172 may include two sensing regions(corresponding to sensing regions E1 and E2) in its midsections 172A and172B, and two sensing regions (corresponding to sensing regions E3 andE4) in its side sections 172C and 172D. The sensor assembly 174 may belikewise constructed. By providing multiple, discrete sensing regions,the sensing system 170 can provide improved detection resolution.

Aspects of the finger 100 provide a number of advantages relating tocost and ease of manufacture. In general, the vertebrae, tensioningsystem 160 and sensor system 170 simplify the components and proceduresrequired to construct the finger 100.

The tendon cables 156, 158 and guide members 118 are located in theradially outer portions of the phalanxes 110-116, leaving the centralbores empty for routing sensor wiring.

The tendon cables 156, 158 form a part of the drive system 150 and thetensioning system 160, and also couple and maintain the relativepositioning of the skeletal components, the phalanxes 110-116 and thevertebrae V1-V6. By using the tendon cables 156, 158 to effect motiondrive, suspension and impact control, the layout and assembly of thefinger 100 are simplified.

As described above, in embodiments, the sensor assemblies 172, 174, 176are premounted on the phalanxes, and these subassemblies and thevertebrae V1-V6 and guide members 118 are serially stacked from thedistal end to the proximal end. The tendon cables 156, 158 are threadedinto the finger 100 and terminated. This modular assembly procedure isdesigned for execution with no special equipment or skill. Thus, theconfiguration and methods of the finger 100 enable more efficient andcost-effective construction.

As described above, in embodiments, each of the tendon cables 156, 158includes two parallel strands 156B, 158B (FIG. 3) connected at a closedloop 156A, 158A at its distal terminal end (e.g., a single continuousstrand is folded 180 degrees at the distal end) and secured by the pin149. This dual strand tendon arrangement provides additional loadcapacity while evenly balancing the load between the two strands. Thedual strands increase the push strength for insertion of the tendoncables 156, 158 into the raceways 124, 124B, 144A, 144B during assembly.The distal end of each tendon cable can be secured without cutting thetendon cable material, which cutting may otherwise cause fraying of thetendon cable that would interfere with assembly. The tendon cables 156,158 are preterminated to the distal phalanx 116 and the spool 154 priorto installing the finger 100 on the base 20. The tendon cable paths aresmooth and/or contoured to eliminate sharp corners.

The raceways 124A of the phalanxes 110-116 and the raceways 144A of thevertebrae V1-V6 collectively define or form an inner combined via orraceway 125A (FIG. 11) extending axially continuously the length of thefinger 100 from the base member 110A to the distal phalanx 116. Likewisethe raceways 124B and 144B collectively define an outer combined raceway125B extending axially continuously from the base 110A to the distalphalanx 116. The tendons 156 and 158 extend continuously through theinner and outer combined raceways 125A and 125B, respectively. Inembodiments, the raceways 125A, 125B each constitute a continuous smoothsurface, even in the finger overload state where the joints JP, JM, JDare stretched apart. The openings of the raceways 124A, 124B, 144A, 144Bare beveled or rounded to guide the tendon cables 156, 158 to bend andflex without hitting sharp corners.

Fingers and methods as disclosed herein can provide a number ofadvantages in operation, manufacture and cost reduction. As discussedabove, the components of the finger 100 are conveniently andcost-effectively assembled by stacking.

The configuration and arrangement of the finger components leaves arelatively large central bore 135 through which the sensor system leadwires WP, WM, WD (and other parts if needed) are routed.

The sensor assemblies 172, 174, 176 are relatively thin and compact sothat they are integrated with the finger without requiring substantialenlargement of the finger.

The use of the common trace CG for each sensor assembly 172, 174, 176eliminates the need for a separate return (e.g., ground) wire for eachof the sensors and sensing regions. This reduces the number of wiresthat must be routed from the PCB through the finger and thereforereduces the space required in the finger 100 to accommodate these wires.Because the finger has limited space to accommodate lead wires, thisaspect can make possible the provision of multiple discrete sensors andsensing regions as described.

Notably, all of the electronic components of each sensor assembly 172,174, 176 are located interior of the conductive layer 186 and theprotective cover layer 148. Therefore, the conductive layer 186 and theoptional protective cover layer 148 are the only moving parts of thesensor assembly.

With reference to FIGS. 23 and 24, a robotic finger 200 according tofurther embodiments of the invention is shown therein. The finger 200corresponds to and may be constructed in the same manner as the finger100, except that the finger 200 includes a tensioning system 260 inplace of the tensioning system 160.

The tensioning system 260 includes an inner swingarm 262A pivotallymounted on a housing 210B by a pivot pin 262B. The tensioning mechanism260 further includes an outer swingarm 264A pivotally mounted on thehousing 210B by a pivot pin 264B. An inner guide roller 262 and an outerguide roller 264 are mounted on the swingarms 262A and 264A,respectively. Five stacked leaf springs 266 are connected in seriesbetween the swingarms 262A and 262B. In some embodiments, the leafsprings 266 are formed of a polymer such as a plastic material. An innerlinkage 265A and an outer linkage 265B are provided between the leafsprings 266 and the inner swingarm 264A and the outer swingarm 264B totransmit the spring force of the leaf springs 266 to the guide rollers262 and 264.

The tensioning system 260 is arranged such that, when the finger 200 isin its neutral position, the springs 266 are elastically deflected andbias or force the guide rollers 262 and 264 in the proximal direction tomaintain a tension load on the tendon cables 256, 258 as described abovewith regard to the finger 100. In the neutral position, the springs 266,the linkages 265A, 265B and the guide rollers 262, 264 retain sufficientspace to permit the guide rollers 262, 264 to travel in the distaldirection in response to a load applied to the finger 200.

With reference to FIGS. 25-27, a robotic finger 300 according to furtherembodiments is shown therein. The finger 300 corresponds to and may beconstructed in the same manner as the finger 100, except that the finger300 includes a tensioning system 360 in place of the tensioning system160 and the drive spool and motor (not shown in FIGS. 25-27) is locatedoff of the finger 300 (e.g., in the base 20).

The tensioning system 360 includes an inner swing arm or drum 262Arotatably mounted on a fixed post 310C of a housing 310B. The tensioningsystem 360 further includes an outer swing arm or drum 364A rotatablymounted on the post 310C. An inner guide roller 361, an outer guideroller 364 and a fixed guide roller 368 are disposed between the drums362A, 364A. The inner guide roller 362 is rotatably mounted (by a pin362B) on the drum 362A for travel therewith. The outer guide roller 364is rotatably mounted (by a pin 364B) on the drum 364A for traveltherewith. The fixed roller 368 is rotatably mounted on the post 310C bya pin 368B. The fixed roller 368 can rotate about the pin 368 but isotherwise fixed in position relative to the housing 310B. Torsionsprings 366 are seated or housed in spring cavities 362A, 364D definedin the lateral outer sides of the drums 362A, 364A. The torsion springs366 are also anchored to the housing 310B in housing side wall cavities310E.

FIG. 27 illustrates the finger 300 in four different operational statesor poses in views (a), (b), (c) and (d). With reference to view (a), theinner tendon cable 356 is routed over the roller 368, across to and overthe inner roller 362, and through the phalanxes and vertebrae asdescribed above and is anchored in the distal phalanx 316. A proximalsection 356D of the tendon cable 356 extends to the drive spool or otherdrive mechanism. Similarly, the outer tendon cable 358 extends over theroller 368, across to and over the outer roller 364, and through thephalanxes and vertebrae as described above and is anchored in the distalphalanx 316. A proximal section 358D of the tendon cable 358 extends tothe drive spool or other drive mechanism.

View (a) of FIG. 27 illustrates the configuration assumed by thetensioning system 360 when the finger 300 is in its neutral position.

View (b) of FIG. 27 illustrates the position or configuration assumed bythe tensioning system 360 when the finger 300 is subjected to a forcetending to force the finger upward or open, or when the drive system isoperated to close the finger 300 and the finger 300 is fully closed orotherwise encounters resistance.

View (c) of FIG. 27 illustrates the position or configuration assumed bythe tensioning system 360 when the finger 300 is subjected to a forcetending to force the finger 300 downward or closed, or when the drivesystem is operated to open the finger 300 and the finger 300 is fullyopen or otherwise encounters resistance.

View (d) of FIG. 27 illustrates the position or configuration assumed bythe tensioning system 360 when the finger 300 is subjected to a lateralor sideward force.

In each of the views (a)-(d), the tensioning system 360 is shown withthe extended tendon cable or cables 356, 358 in their overloadedpositions; that is, in the position assumed when the force acting on thefinger pulls the associated roller or rollers to its or their forwardposition(s). In this position, the associated drum 362A, 364A and roller362, 364 operate effectively as a two-force member as described above sothat the full tension on the tendon cable 356, 358 is transferred to thehousing 310B.

The tensioning system 360 reduces the overall required volume of themechanism by locating the drums 362A, 364A on either side of the centralfixed roller 368 and locating the springs 366 inside the drums 362A,364A.

Fingers according to some embodiments may include more or fewerphalanxes and vertebrae. In some embodiments, one or more of the knucklejoints is provided with three or more vertebrae arranged in seriesbetween the connected phalanxes. In some embodiments, at least one ofthe knuckle joints includes only a single vertebra. The fingers mayinclude more or fewer than four phalanxes and three knuckle joints. Asdiscussed above, using a greater number of vertebrae can enable largerjoint angles, smaller gaps between adjacent vertebrae, and more gradualtendon paths.

According to further embodiments, the PCBs 180 of the sensor assemblies172, 174, 176 may be replaced with alternative substrates bearing thetrace patterns 184. In some embodiments, an electrically conductive inkis applied directly to the polymeric phalanx bodies 120 of the phalanxes112-116. In some embodiments, the conductive ink is screen printed ontothe bodies 120. In some embodiments, the conductive ink is 3D printedonto the bodies 120.

In some embodiments, the trace 184 is provided as a metal foil tape thatis secured (e.g., by adhesive) directly to the phalanx. The foil tapemay be die-cut, laser cut or otherwise shaped in the form of the tracepattern 184.

In some embodiments, the trace pattern 184 is provided on a flex circuitthat is secured to the phalanx. The flex circuit may include a flexiblesubstrate formed of a polymeric material such as polymide, PEEK orpolyester.

As discussed above, in some embodiments, the electrically conductivelayer 186 is a semiconductor layer and, in particular, may be a flexiblepolymeric film or layer filled with electrically conductive particles.In other embodiments, the conductive layer 186 may instead be anelectrically conductive metal foil that provides substantially an on/offresponse to applied pressure rather than a response that varies inproportion to the amount of the pressure.

In further embodiments, the electrically conductive layer 186 is omittedand the elastomeric cover member 148 (finger pad) is formed of anelectrically conductive polymer. The conductive polymer may be a stockmaterial or electrically conductive filler or additive material (e.g.,particles) may be mixed into the molded or extruded cover member 148during manufacture.

In further embodiments, the conductive layer 186 may be omitted and anelectrically conductive or semiconductor layer may be applied directlyto the inner surface of the cover member 148. The electricallyconductive or semiconductor layer may be electroplated, sputter coated,metalized or sprayed onto the inner surface of a rubber/foam covermember 148, for example.

In further embodiments, the conductive layer 186 may be omitted and thesensor assembly may be modified to provide inductive or capacitivesensing of a metal filler (e.g., powder) or foil embedded in acompressible cover member 148 (finger pad). The sensor assembly maychange its resistance responsive to and in proportion to the amount ofcompression of the cover member material in a direction generallyorthogonal to the trace pattern.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention. Therefore,it is to be understood that the foregoing is illustrative of the presentinvention and is not to be construed as limited to the specificembodiments disclosed, and that modifications to the disclosedembodiments, as well as other embodiments, are intended to be includedwithin the scope of the invention.

That which is claimed is:
 1. A robotic end effector comprising: a fingerextending from a proximal end to a distal end along a finger axis, thefinger comprising: a first phalanx proximate the proximal end; a secondphalanx proximate the distal end; a knuckle joint including at least onevertebra interposed between and separating the first and secondphalanxes, wherein: the knuckle joint is configured to permit the secondphalanx to pivot relative to the first phalanx about a pivot axistransverse to the finger axis; and each vertebra has an axial thicknessextending along the finger axis and a lateral width extendingperpendicular to its axial thickness, and its lateral width is greaterthan its axial thickness; at least one actuator to move the secondphalanx relative to the first phalanx about the pivot axis; and a tendoncable associated with the at least one actuator for moving the secondphalanx relative to the first phalanx about the pivot axis; wherein thetendon cable extends through the at least one vertebra and applies anaxially compressive load to the first phalanx, the second phalanx andthe at least one vertebra to hold the first phalanx, the second phalanxand the at least one vertebra together and in contact with one another.2. The robotic end effector of claim 1 wherein each of the first andsecond phalanxes has a phalanx length that is at least 2 times the axialthickness of each of the vertebrae.
 3. The robotic end effector of claim1 wherein the lateral width of each of the vertebrae is at least 1.5times its axial thickness.
 4. The robotic end effector of claim 1wherein each of the vertebrae has a height perpendicular to each of itsaxial thickness and its lateral width, and the axial thickness of thevertebra varies across the height of the vertebra.
 5. The robotic endeffector of claim 1 wherein at least one of the vertebrae includes anonplanar bearing surface that engages an adjacent bearing surface ofone of the first phalanx, the second phalanx, and an adjacent vertebra.6. The robotic end effector of claim 5 wherein the bearing surface hasat least one substantially planar section.
 7. The robotic end effectorof claim 5 wherein the bearing surface includes: an outer stop faceconfigured to limit rotation of the first phalanx about the pivot axisin a first bending direction; and an angled inner face disposed at anoblique angle to the outer stop face to permit rotation of the firstphalanx about the pivot axis in a second bending direction opposite thefirst bending direction.
 8. The robotic end effector of claim 7 whereinthe bearing surface further includes a neutral face located between theouter stop face and the inner angled face and disposed at an obliqueangle to the outer stop face and the angled inner face.
 9. The roboticend effector of claim 1 wherein the at least one vertebra includes aplurality of vertebrae serially arranged between the first phalanx andsecond phalanxes.
 10. The robotic end effector of claim 9 wherein the atleast one vertebra includes at least three vertebrae serially arrangedbetween the first phalanx and second phalanxes.
 11. The robotic endeffector of claim 9 wherein each of the plurality of vertebrae includesa nonplanar bearing surface that engages an adjacent bearing face of oneof the first phalanx, the second phalanx, and an adjacent vertebra. 12.The robotic end effector of claim 9 wherein at least two of thevertebrae have different axial thicknesses from one another.
 13. Therobotic end effector of claim 1 including: a third phalanx proximate thedistal end of the finger; a second knuckle joint including at least onevertebra interposed between and separating the second and thirdphalanxes, wherein: the second knuckle joint is configured to permit thethird phalanx to pivot relative to the second phalanx about a secondpivot axis transverse to the finger axis; and each vertebra of thesecond knuckle joint has an axial thickness and a lateral widthextending perpendicular to its axial thickness, and its lateral width isgreater than its axial thickness; and wherein the at least one actuatoris operable to move the third phalanx relative to the second phalanxabout the second pivot axis.
 14. The robotic end effector of claim 1including an elongate, flexible guide member extending from the firstphalanx to the second phalanx and through the at least one vertebra toflexibly couple the first and second phalanxes and the at least onevertebra and retain the at least one vertebra between the first andsecond phalanxes.
 15. The robotic end effector of claim 14 wherein theguide member has a Young's modulus of less than about 2.4 GPa at 23degrees Celsius.
 16. The robotic end effector of claim 1 including atensioning mechanism to maintain the axially compressive load.
 17. Therobotic end effector of claim 1 wherein the tensioning mechanismincludes a spring applying a biasing load to the tendon cable.
 18. Therobotic end effector of claim 1 including: first and second tactilesensors mounted on the first and second phalanxes, respectively; whereinthe at least one vertebra does not or do not include tactile sensorsmounted thereon.
 19. The robotic end effector of claim 18 includingelectrical wires electrically connected to the second tactile sensor andextending from the second phalanx and through the at least one vertebra.20. The robotic end effector of claim 1 wherein the at least onevertebra is or are formed of a polymeric material.
 21. A robotic endeffector comprising: a finger extending from a proximal end to a distalend along a finger axis, the finger comprising: a first phalanxproximate the proximal end; a second phalanx proximate the distal end; aknuckle joint including at least one vertebra interposed between andseparating the first and second phalanxes, wherein: the knuckle joint isconfigured to permit the second phalanx to pivot relative to the firstphalanx about a pivot axis transverse to the finger axis; and eachvertebra has an axial thickness extending along the finger axis and alateral width extending perpendicular to its axial thickness, and itslateral width is greater than its axial thickness; a third phalanxproximate the distal end of the finger; a second knuckle joint includingat least one vertebra interposed between and separating the second andthird phalanxes, wherein: the second knuckle joint is configured topermit the third phalanx to pivot relative to the second phalanx about asecond pivot axis transverse to the finger axis; and each vertebra ofthe second knuckle joint has an axial thickness and a lateral widthextending perpendicular to its axial thickness, and its lateral width isgreater than its axial thickness; and at least one actuator to move thesecond phalanx relative to the first phalanx about the pivot axis, andto move the third phalanx relative to the second phalanx about thesecond pivot axis.
 22. A robotic end effector comprising: a fingerextending from a proximal end to a distal end along a finger axis, thefinger comprising: a first phalanx proximate the proximal end; a secondphalanx proximate the distal end; a knuckle joint including at least onevertebra interposed between and separating the first and secondphalanxes, wherein: the knuckle joint is configured to permit the secondphalanx to pivot relative to the first phalanx about a pivot axistransverse to the finger axis; and each vertebra has an axial thicknessextending along the finger axis and a lateral width extendingperpendicular to its axial thickness, and its lateral width is greaterthan its axial thickness; and an elongate, flexible guide memberextending from the first phalanx to the second phalanx and through theat least one vertebra to flexibly couple the first and second phalanxesand the at least one vertebra and retain the at least one vertebrabetween the first and second phalanxes; and at least one actuator tomove the second phalanx relative to the first phalanx about the pivotaxis.